Media access control (MAC) protocol for cognitive wireless networks

• US 8,879,573 B2
• Filed: 08/29/2007
• Issued: 11/04/2014
• Est. Priority Date: 12/01/2006
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bahl, Paramvir, Chandra, Ranveer, Moscibroda, Thomas, Narlanka, Gopala Sri Hari, Wu, Yunnan, Yuan, Yuan
• Primary Examiner(s): HUYNH, KHOA B
• Application Number:
  US11/847,034
• Publication Number:
  US 20080130519A1
• Time in Patent Office: 2,624 Days
• Field of Search: 370/229, 370/230, 370/230.1, 370/235, 370/241, 370/252, 370/310, 370/345, 370/347, 370/348, 370/431, 370/433, 370/436, 370/437, 370/438, 370/439, 370/442, 370/443, 370/445, 370/447, 370/449, 370/458, 370/459, 370/462, 370/464, 370/465, 370/468, 375/130, 375/140, 375/141, 375/240, 375/240.01, 375/240.02, 455/403, 455/422.1, 455/434, 455/450, 455/462, 455/464, 455/39, 455/500, 455/507, 455/509, 455/515, 455/130, 455/150.1, 455/179.1, 709/223, 709/224, 709/225, 709/226
• US Class Current: 370/445
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/0882 Utilisation of link capacity
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A new media access control (MAC) protocol for cognitive wireless networks is described. The new MAC protocol allows each of multiple nodes, such as cell phones and computers with wireless, to determine utilization of a communication spectrum, such as the television broadcast band. The nodes collaborate to achieve a combined view of spectrum utilization in their local vicinity, in which scheduled users and empty time segments are mapped across a wide range of frequencies. Nodes negotiate with each other to reserve idle segments of the spectrum for packet exchange on negotiated frequencies. Control packet structure allows nodes to become prescient of the local spectrum utilization during handshaking. A cognitive device operating under the new MAC has a first radio that both scans the spectrum and monitors a control channel; and a second reconfigurable radio with adjustable parameters, including frequency and bandwidth, for packet transmission.

Claims

1. A method, comprising:

under control of one or more computer systems configured with executable instructions,

monitoring, by a scanner radio of a network node, a control channel to identify spectrum reservations announced by additional network nodes in communication with each other;

determining, by the network node, a utilization of a communication spectrum at each of the additional network nodes based on the monitoring of the control channel;

aggregating, by the network node, the utilizations from at least some of the additional network nodes into an aggregated utilization of the communication spectrum;

reserving, by the network node, a part of the communication spectrum for an exchange of information based on the aggregated utilization using the control channel, the control channel being an unfixed control channel having a lower transmission range than transmission ranges associated with the exchange of information;

scanning, by the scanner radio of the network node, a particular portion of the communication spectrum to identify vacant portions of the communication spectrum for an exchange of packets with the particular additional network node;

monitoring the control channel, by an additional radio of the network node, while the scanner radio is scanning the particular portion of the communication spectrum; and

after the scanner identifies vacant portions of the communication spectrum for the exchange of packets with the particular additional network node, tuning the additional radio of the network node to the identified vacant portions of the communication spectrum to perform the exchange of packets with the particular additional network node.

2. The method as recited in claim 1, wherein reserving a part of the communication spectrum includes negotiating a resource block in the communication spectrum, between the network node and a particular additional network node.

3. The method as recited in claim 2, wherein negotiating the resource block includes determining an available frequency in the communication spectrum, determining a bandwidth around the frequency, determining a starting time, and determining a duration for the exchange of information using the frequency and the bandwidth.

4. The method as recited in claim 2, wherein the negotiating includes sending a request-to-send (RTS) packet from the network node to the particular additional network node, wherein the RTS packet structure contains a view of the spectrum utilization at the network node.

5. The method as recited in claim 2, wherein the negotiating includes sending a request-to-send (RTS) packet from the network node to the particular additional network node, wherein the RTS packet structure designates candidate idle segments of the spectrum.

6. The method as recited in claim 2, wherein the negotiating includes receiving a clear-to-send (CTS) packet from the particular additional network node, wherein the CTS packet structure contains a view of the spectrum utilization at the particular additional network node and the CTS packet structure designates candidate idle segments of the spectrum.

7. The method as recited in claim 2, wherein the negotiating includes sending a data transmission reservation (DTS) packet from the network node to the particular additional network node, wherein the DTS packet structure contains a reservation defining a segment of the spectrum to reserve, wherein the reservation includes a frequency, a bandwidth around the frequency, a starting time, and a duration.

8. The method as recited in claim 1, wherein determining a utilization comprises determining a utilization of the television broadcast spectrum.

9. The method as recited in claim 1, wherein data exchanged on the unfixed control channel informs the network node and one or more of the additional network nodes of the spectrum utilization viewed at particular additional network nodes.

10. The method as recited in claim 1, further comprising:

storing the spectrum utilization in a matrix at the network node; and

sharing at least part of the matrix with one or more of the additional network nodes.

11. The method as recited in claim 1, wherein determining a utilization of the communication spectrum includes scanning the communication spectrum to determine current users and their associated frequencies.

12. The method as recited in claim 1, wherein determining a utilization of the communication spectrum includes monitoring the unfixed control channel to update the aggregated utilization of the communication spectrum.

13. A cognitive wireless network system, comprising:

a scanner radio;

an additional radio;

a network node comprising a cognitive wireless networking engine configured to;

implement a cognitive media access control (MAC) protocol that provisions collaborative sensing of communication spectrum utilization by a plurality of additional network nodes via a communication control channel common to the network node and the plurality of additional network nodes via the scanner radio, wherein the communication control channel comprises a shorter wireless range of frequency than a range of wireless frequencies reserved for data exchange and wherein the communication control channel is configured to hop across multiple channels within a spectrum of control frequencies;

determine whether an output queue of the network node includes a threshold number of packets;

monitor the communication control channel;

determine whether an output queue of an other network node includes a particular number of packets via the communication control channel; and

negotiate and reserve idle blocks of the communication spectrum via the communication control channel to exchange data with the other network node via the additional radio based at least in part on a determination that the output queue of the network node includes at least the threshold number of packets and a determination that the output queue of the other network node includes at least the particular number of packets, the data to be exchanged including data of the output queue of the network node and the output queue of the other network node.

14. The cognitive wireless network system as recited in claim 13, wherein the network node and the plurality of additional network nodes negotiate adaptive spectrum allocation such that the network node and the plurality of additional nodes self-organize into a network without coordination from a central controller.

15. The cognitive wireless network system as recited in claim 13, wherein the network node and each of the plurality of additional network nodes include a first radio for scanning the communication spectrum for the idle blocks and a second radio tunable to idle blocks of various frequencies for data communication.

16. The cognitive wireless network system as recited in claim 15, wherein the first radio or the second radio also monitors the movable communication control channel.

17. The cognitive wireless network system as recited in claim 16, wherein the network node reserves a part of the communication spectrum via the movable communication control channel before scanning the part of the communication spectrum.

18. The cognitive wireless network system as recited in claim 13, wherein the movable communication control channel uses a higher frequency than frequencies reserved for data exchange.

19. A network node, comprising:

a memory;

one or more processors operatively coupled to the memory;

a first set of conventions, stored in the memory and executable on the one or more processors, for achieving collaborative sensing of a communication spectrum via combining scanning results communicated from an unfixed control channel; and

a second set of conventions, stored in the memory and executable on the one or more processors, for reserving idle parts of the communication spectrum using the unfixed control channel for an exchange of information, the unfixed control channel having a lower transmission range than transmission ranges associated with the exchange of information; and

a cognitive wireless networking engine, stored in the memory and executable on the one or more processors, for reserving the idle parts of the communication spectrum by sending to the additional network node a request to send packet including a plurality of proposed candidate spectrum segments for the network node to communicate with the additional network node, receiving from the additional communication device a clear to send packet indicating a particular spectrum segment of the plurality of proposed candidate spectrum segments that is to be used for data exchange between the network node and the additional network node, sending to the additional communication device a data transmission reservation packet to acknowledge reservation of the particular spectrum segment for data exchange between the network node and the additional network node, and transmitting one or more packets to the additional network node via the particular spectrum segment.